Nov 17 01:51:53 NAS mcelog: CPU 2 on socket 0 has large number of corrected cache errors in Level-2 Instruction
Nov 17 01:51:53 NAS mcelog: System operating correctly, but might lead to uncorrected cache errors soon
Doesn't look good. I'd say CPU issue, and with the number of errors being reported, probably best to replace the cpu
Or to put it another way, a beta / alpha release CPU that may have issues.